Automatic electric switching device



Jan. 12, 1932. H. A. H. NIJLAND AUTOMATIC ELECTRIC SWITCHING DEVICE Filed Dec. 21. 1927 5 Sheets-Sheet 1 I Jan. 12, 1932.

H. A. H. NIJLAND AUTOMATIC ELECTRIC SWITCHING DEVICE Filed Dec. 21. 1927 3 Sheets-Sheet 2 Jan. 12, 1932. H. A. H. NIJLAND AUTOMATIC ELECTRIC SWITCH ING DEVICE Filed Dec. 21. 1927 3 Sheets-Sheet 3 Patented Jan. 12, 1932 UNITED STATES PATENT OFFICE HENDRIK AR-END HIDDE NIJLAND, OF ZEIST, NETHERLANDS AUTOMATIC ELECTRIC SWITCHING DEVICE Application filed December 21, 1927,'Seria1 No. 241,579, and in the Netherlands January 14, 1925.

This invention relates to an automatic electric circuitclosing device for changing over the feeding point from one electricfeeder to a reserve electric feeder in the event a dis- 5 turbance occurs in the first mentioned feeder.

Itis generally known that, in order to feed an important feeding point or consumption point in the most reliable way with electrical energy, it is usual to connect this pointto two 10 cables or feeders, leading from the same or from different generating stations to the feed ing point.

However, this double connection is of questionable value if both cables, under normal conditions, are always in connection with the outgoing cable and are protected only by a usual form of safety device. Accordingly, it has-been proposed to employ in conjunction with the double connection special safety sysare connected with an automatic electric cir- 1 cuit closing device, whereby when onefeeder cable is disturbed the supply cable is automatically connected to the other feeder cable.

Moreover, when the two feeders are connected in ring form, the inventionprovides means whereby the ring is opened directly at the feeding point in the event one branch is disturbed. According to the invention, the propose automatically acting circuit closing device is provided with a plurality of controlling coils which are energized to actuate suitable switch other of the feeder cables.

means when a disturbance occurs in one or the F or a better understanding of the inven titan-reference is made to the accompanying drawings, wherein Figure 1 is a general diagram ofthe invention as employed in connection with a feeding point fed by two feeders;

Fig. 2 is a diagram of the invention as employed in connection with a ring circuit;

Fig. 3 is a diagram similar to Fig. 2, showing a modified form of the invention.

Considering the drawings more in detail, Figure 1 shows two feeders 1 and 2 adapted to be connected to an outgoing cable 3. In the circuit of the feeders are arranged voltage transformers 4t and 5, the secondary coils of which are connected to coils 6 and 7 of a differential voltage relay, the armature 8 of which cooperates with contacts 9, 10, 11 and 12. The contacts 11 and12 are interconnected and are also connected with one terminal of a suitable current source, such as a battery (not shown). The contacts 9 and 10, on the other hand, are connected respectively with one terminal of controlling coils 14 and 13 of an automatic reversing switch.

These coils actuate armatures 15 and 16, whichare connected attheir lower ends to a balance lever 17, provided at each end with a contact arm 18, 19, which cooperate with contacts 20, 21, 22 and 23, and thereby establish connection between the-cable 3 and either the feeder-1 or the feeder2.

In the outgoing cable 3 is connected a current transformer 25, the secondary coil of which is connected with the coil of an auxiliary relay 26. The armature of this relay is adapted to connect two contacts 27 and 28, of which contact 27 isconnected to one terminal of each of the controlling coils 13 and 14, and contact28 is connected to the other terminal of V the suitable current source mentioned above.- The relay 26 is so adapted that when its coil isenergized, the armature is drawn up and locked in position, where it remains until released by hand or other suitable means.

Assuming a hypothetical case wherein the apparatus is in the position shown in Fig. 1, the operation of the circuit closing device, will be asfollows: As soon as a disturbance occurs in the feeder 2, the voltage therein will drop below the normal value, with the result that the coil 6, energized through the transformer i by the normal voltage in feeder 1, will pull up the armature 8 of the dill erential relay and close the contacts 9 and 1. Upon closing of the contacts 9 and 12, the controlling coil 14 is energized by curren from the separate source and the armature 16 is pulled up, whereupon the balance lever 17 is tilted and contacts 20 and 21 are closed by the contact arm 18 to establish connection between the cable 3 and the feeder 1.

In the event a disturbance occurs in the feeder 1, after its connec ion to the cable 3, and its voltage decreases in consequence, the differential relay will drop its armature under the influence of the coil 7 d connect contacts 10 and 11, because the voltage in coil (3 will then be less th the voltage in coil 7. The controlling coil 13 will then be energized from the SGptlltl'tQ current ource and will draw up its armature 15 and tilt the balance lever 17 to connect the contacts 23 by means of the contact arm 1'9.

On occasion, a disturbance may occur in the outgoing cable 3, and a current of h' h value appear in this cable. To guard against this contingency, the auxiliary relay energized by the transformed is provided. Accordingly, should a current of high value appear in cable 3, the relay 26 will be energized to draw up and lock its armature in its upper position and thus break the connection between the contacts 27 and 28 controlling; the common connection between the coils and 1e: and the current source. So long the arn'iature remains in its locked position, the circuit of the coils 13 and M remains open and the circuit closing mechanism is held inoperative. Only after the armature has been released as upon disappearance of the disturbance in cable 3, will the circuitclosing mechanism again become operative.

In Fig. 2 is indicated the diagram of a ring connection wherein 1 and 2 indicate the two feeder branches and 3 the outgoing cable branch. A by-pass or bridge connection is placed about this branch point in order to connect the two feeder branches of the ring cable. In addition to the circuit closingmechanism shown in Fig. 1, the arrangement is provided with a minimum voltage switch 24: located in the bridge connection. The coil of this switch is so constituted that when the voltage therein drops below a predetermined value the switch will be opened.

In nig. 3 an arrangement similar to that in Fig. 2 is shown, with the ditli'erence that the voltage transformers t and 5 are employed to serve as a current source for the controlling coils 13 and l l instead of a separate current source. The relay 26 is accordingly provided with two sets of contacts 27,

28 and 29, 30, of which one set relates to the coil 13 and the other to the coil i l.

Aside from the operation of the additional elements shown in digs. 2 and 3, the ope tie-n of the arrangements therein illustrated is the same as that of the apparatus shown in 1 claim 1. The combination with a supply cable, a main feeder and a reserve feeder cable, of an automatic switching device, comprising a beam oscillatable about a pivot, a switch carried at opposite ends of the beam and arranged to transfer th load from one feeder to the other, solenoids exerting, when energized, a pull upon said beam at opposite sides of its pivot, said beam being returnable by hand to its neutral position when both solcnoids are deenergized, am: a differential responsive to the electrical condition of said feeder cables for selectively energizing said sol cnoids.

2. The combination with a supply cable, a

' cable and a reserve feeder cable,

emetic switching device, comprisoscillatable about a pivot, a switch )posite ends of the beam and arins'lier the load from one feeder solenoids exerting a pull upon the beam at opposite sides of its pivot when eneio'ized, said beam being returnable by i 1 te its neutral position when both solenerds are deenergized, a transformer in each cable, a ditl'erential relay connected in circuit with each of said transformers, a t:'ansformer in said supply cable, and an auxiliary relay connected in circuit with said 3 er transformer and arranged to de-enen ime said solenoids when a disturbance occurs to the 0th 1,

in said supply cable.

in testimony whereof, I. have signed my name to this specification.

HENDRIX AREND HIDDE lllJLAND. 

